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Multi-Physics Material Modeling
Altair Material Modeler is a collection of data fitting tools for polymers in a single cohesive studio environment with a workflow designed around using the results for various manufacturing and structural simulations including injection molding, extrusion, temperature-dependent structural simulation, short fiber multiscale modeling, and hyperelastics.
Temperature-Dependent Modeling
Many manufacturing and other engineering applications require a thermal component to the material characterization. Thermal analyses and mechanical analyses involving temperature sensitive mechanical properties of polymers and other advanced materials frequently require a multi-physics approach to their analysis and thus the properties of the material. As these thermal properties will change with temperature Material Modeler has, and is continuing to develop modeling of these thermal properties with respect to temperature to support the growing segment of thermal-mechanical simulation and analysis.
Specific Heat
The specific heat content for a material is the amount of energy it takes to raise one unit of mass (i.e. kg) of that material by one degree (i.e. Kelvin). It is also the derivative with respect to temperature of the Specific Enthalpy for the material. For 2024.1 the Specific Heat can be imported, and exported as a table for injection molding applications, and a plot generated for visualization. The specific enthalpy can be imported and a plot generated for visualization, but the fitting of the Specific Enthalpy has not yet been implemented.

Welcome
Altair Material Modeler
Generating accurate material properties can be a time-consuming process, Altair Material Modeler (AMM) is a sophisticated modeling software that efficiently processes material data from testing to generate simulation-ready material cards for analyzing the nonlinear behavior of bulk materials as well as the various physical properties of materials, such as polymers and elastomers, used in the manufacture of modern products.
What's New
Here’s a quick look at the latest features available with Altair Material Modeler.
Tutorials
Discover the features of Altair Material Modeler with interactive tutorials.
Elastoplastic Material Modeling
This chapter provides information from preparing data to generating a material card.
Multi-Physics Material Modeling
Altair Material Modeler is a collection of data fitting tools for polymers in a single cohesive studio environment with a workflow designed around using the results for various manufacturing and structural simulations including injection molding, extrusion, temperature-dependent structural simulation, short fiber multiscale modeling, and hyperelastics.
- Material Overview Page
- Specific Volume (pvT) Fitting
  Specific Volume is the inverse of Specific Gravity, and its dependence on temperature and pressure forms an equation of state from which several physical quantities can be derived. The Specific Volume Fitter is a sophisticated tool designed to fit specific volume test data of a polymer or composite to various mathematical models beginning with the Tait model, and it is currently executed from the Material Modeler - Polymer application or via the Compose REPL. This function is compatible with data from various testing machines.
- Shear Viscosity
  Once the file is imported and the viscosity data is fit, the Cross Model with Williams -Landel-Ferry (WLF) is displayed as the default viscosity model pair. To inspect other options, choose a model for shear viscosity or temperature dependence to review the Viscosity vs Shear Rate and Temperature.
- Recommend Process Conditions
  At the start of the process, default settings for molding and extrusion are loaded based on the polymer family. Each type of thermoplastic polymer has default values for parameters like minimum and maximum melt temperatures. These values are pre-set defaults based on common standards, and are meant to be replaced when specific values are known. These serve as reference values in simulation setup and in post processing, depending on the specific quantity.
- Temperature-Dependent Modeling
  Many manufacturing and other engineering applications require a thermal component to the material characterization. Thermal analyses and mechanical analyses involving temperature sensitive mechanical properties of polymers and other advanced materials frequently require a multi-physics approach to their analysis and thus the properties of the material. As these thermal properties will change with temperature Material Modeler has, and is continuing to develop modeling of these thermal properties with respect to temperature to support the growing segment of thermal-mechanical simulation and analysis.
  - Thermal Conductivity
    For the initial release, only scalar values and the initial table values can be used for thermal conductivity and specific heat in the output. A file with a table of values can be imported and a plot is automatically generated. Use the plot to estimate a scalar value and enter it in the field directly below the selection box.
  - Specific Heat
    The specific heat content for a material is the amount of energy it takes to raise one unit of mass (i.e. kg) of that material by one degree (i.e. Kelvin). It is also the derivative with respect to temperature of the Specific Enthalpy for the material. For 2024.1 the Specific Heat can be imported, and exported as a table for injection molding applications, and a plot generated for visualization. The specific enthalpy can be imported and a plot generated for visualization, but the fitting of the Specific Enthalpy has not yet been implemented.
  - Moduli vs Temperature
    The Tait model and parameters for Specific Volume are used to obtain the Bulk Modulus of the material over a range of temperatures taken from a table of either elastic or shear moduli vs temperature in order to compute the Poisson's Ratio at those temperatures and fit them to a generalized TANH function. This is only valid for isotropic materials such as unfilled thermoplastic polymers. If a material is fiber filled, this tab takes the Tait parameters from the Multiscale tab after extraction from the pvT of the composite.
- Multiscale Characterization
  Characterization of advanced materials and composites is best done with a multiscale approach. Altair's Multiscale Designer (MDS) is run in batch mode to combine the properties of a neat polymer and the fibers based on their volumetric composition (Forward Characterization). Material Modeler takes the Specific Volume of the Composite and of the fibers in order to construct, and fit to the Tait model, the Specific Volume of the Neat Polymer (Reverse Volumetric Characterization). This can be used along with a table of elastic or shear moduli vs temperature in order to obtain the Poisson Ratio parameters leading to a model for the full isotropic elastic properties of the neat polymer.
- Hyperelastic Material Modeling
  Hyperelasticity is a type of constitutive behaviour for materials like natural rubber that exhibit large non-linear elastic deformations. These materials return to their original shape upon unloading, following a nonlinear stress-strain relationship.
Shear Viscosity

Specific Heat

The specific heat content for a material is the amount of energy it takes to raise one unit of mass (i.e. kg) of that material by one degree (i.e. Kelvin). It is also the derivative with respect to temperature of the Specific Enthalpy for the material. For 2024.1 the Specific Heat can be imported, and exported as a table for injection molding applications, and a plot generated for visualization. The specific enthalpy can be imported and a plot generated for visualization, but the fitting of the Specific Enthalpy has not yet been implemented.

Follow these steps to set up and review specific heat values:

Verify the File Type option before importing a file.
On the Material Overview tab, click the Specific Heat button and select the file containing the material test data.
Alternatively, set the Sel selection box on the Material Overview tab to take a scalar value, and then enter that value in the field before clicking the button. The scalar value will then be transferred to the Specific Heat tab for approval.
You can also import Specific Enthalpy, and a plot will be generated.
Note: This release does not compute the slopes, which represent the specific heat values.
Select the Specific Heat (Cp) capacity Model value from the list box. For this initial release this will be a scalar value.
1. Examine the table of specific heat values. For semi-crystalline materials, expect to see a characteristic spike in the data near the phase transition. This spike is due to the fact that the specific heat capacity is the slope of the specific enthalpy with respect to temperature.
2. Identify or estimate a nominal value for specific heat; analytically, this is done by integrating and averaging across the temperature range to give a "path-averaged-value." One can estimate an average value by inspecting the table (e.g., between 2873 and 3528 J/kg·K).
Figure 1. Specific Heat Value
Enter the selected Specific Heat Value (Nominal) value (e.g., 3528 J/kg·K).
Click Approve Model Fit to finalize the setting and approve the model fit for export to a simulation file.